P-268 - Impact of optimal morphologic response on survival in patients with KRAS wild-type unresectable colorectal liver metastases receiving an anti-EGFR o...

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Anticancer agents
Colon and Rectal Cancer
Translational Research
Basic Principles in the Management and Treatment (of cancer)
Therapy
Biological therapy
Presenter T. Masuishi
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors T. Masuishi1, H. Taniguchi1, Y. Narita1, A. Komori1, S. Kadowaki1, T. Ura2, K. Muro1, M. Nomura1, M. Andoh1, T. Eto3
  • 1Aichi Cancer Center Hospital, Nagoya/JP
  • 2Aichi Cancer Center, Nagoya/JP
  • 3Tsuchiura Kyodo General Hospital, Tsuchiura/JP

Abstract

Introduction

FOLFIRI or FOLFOX with either bevacizumab (bev) or anti-EGFR therapy are considered as first-line treatment options for patients with KRAS wild-type colorectal liver metastases (CLM). Early tumor shrinkage (ETS) could be useful as a surrogate marker of the survival benefits of anti-EGFR, while the morphologic response (MR) has been reported to be an early prognostic marker in anti-VEGF therapy. However, little is known about the difference in the survival benefit of these agents according to ETS and MR.

Methods

A retrospective review of a prospectively maintained database of patients who underwent palliative chemotherapy at two institutions (2006-2013) was performed. Three radiologists independently reviewed 135 patients with KRAS wild-type unresectable CLM treated with bev- or anti-EGFR-containing regimens as first-line therapy to assess ETS (330% decrease from baseline) and MR according to morphologic criteria (Shindoh J, et al. J Clin Oncol 2012) at the first follow-up CT compared with baseline CT.

Results

The patients' characteristics were as follows: median age: 64 (range: 27-88), ECOG PS 0-1: 93%, liver-limited disease: 35%, bev/anti-EGFR: 62/38%. The median follow-up time was 24.2 months. In the entire population, progression-free survival (PFS) and overall survival rates showed no difference between bev and anti-EGFR (median PFS: 11.4 vs. 11.3 months, respectively). The optimal MR rate was higher with bev than anti-EGFR (40 vs. 12%, respectively), while the ETS rate was slightly lower (48 vs. 59%, respectively). In patients with ETS, median PFS with bev was shorter than with anti-EGFR (11.1 vs. 15.0 months, HR: 1.49). Conversely, in patients without ETS, the optimal MR rate was higher with bev than anti-EGFR (34 vs. 0%, respectively), and median PFS with bev was longer than with anti-EGFR (12.6 vs. 6.3 months, HR: 0.67).

Conclusion

The ETS rate was higher using anti-EGFR, while the optimal morphologic response rate was higher with bev. Patients showing an optimal morphologic response with bev can be expected to obtain long-term PFS, even in the absence of ETS.